Add renderable axis object
I ended up creating an axis object... Here is the model link in blend swap.
It can create an axis and a few other interesting vectors. To create the axes,
it uses e.g. the input 

vectors = [ 
 [(4,0,0), (0,0,0), 'red'],
 [(0,4,0), (0,0,0), 'green'], 
 [(0,0,4), (0,0,0), 'blue'], 
]